Characterization of vaccine antigens of meningococcal serogroup W isolates from Ghana and Burkina Faso from 2003 to 2009

Neisseria meningitidis is a major cause of bacterial meningitis and a considerable health problem in the 25 countries of the ‘African Meningitis Belt’ that extends from Senegal in West Africa to Ethiopia in the East. Approximately 80% of cases of meningococcal meningitis in Africa have been caused by strains belonging to capsular serogroup A. After the introduction of a serogroup A conjugate polysaccharide vaccine, MenAfriVac™, that began in December 2010, the incidence of meningitis due to serogroup A has markedly declined in this region. Currently, serogroup W of N. meningitidis accounts for the majority of cases. Vaccines based on sub-capsular antigens, such as Generalized Modules for Membrane Antigens (GMMA), are under investigation for use in Africa. To analyse the antigenic properties of a serogroup W wave of colonisation and disease, we investigated the molecular diversity of the protein vaccine antigens PorA, Neisserial Adhesin A (NadA), Neisserial heparin-binding antigen (NHBA) and factor H binding protein (fHbp) of 31 invasive and carriage serogroup W isolates collected as part of a longitudinal study from Ghana and Burkina Faso between 2003 and 2009. We found that the isolates all expressed fHbp variant 2 ID 22 or 23, differing from each other by only one amino acid, and a single PorA subtype of P1.5,2. Of the isolates, 49% had a functional nhbA gene and 100% had the nadA allele 3, which contained the insertion sequence IS1301 in five isolates. Of the W isolates tested, 41% had high fHbp expression when compared with a reference serogroup B strain, known to be a high expresser of fHbp variant 2. Our results indicate that in this collection of serogroup W isolates, there is limited antigenic diversification over time of vaccine candidate outer membrane proteins (OMP), thus making them promising candidates for inclusion in a protein-based vaccine against meningococcal meningitis for Africa.

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Susceptibility of Meningococcal Strains Responsible for Two Serogroup B Outbreaks on U.S. University Campuses to Serum Bactericidal Activity Elicited by the MenB-4C Vaccine

Clinical and Vaccine Immunology ◽

10.1128/cvi.00474-15 ◽

2015 ◽

Vol 22 (12) ◽

pp. 1227-1234 ◽

Cited By ~ 20

Author(s):

Raffaella Rossi ◽

Peter T. Beernink ◽

Serena Giuntini ◽

Dan M. Granoff

Keyword(s):

Bactericidal Activity ◽

The United States ◽

Factor H ◽

Vaccine Antigen ◽

Sequence Variant ◽

Heparin Binding ◽

University Campuses ◽

Vaccine Antigens ◽

High Level ◽

The University

ABSTRACTIn 2013 and 2014, two U.S. universities had meningococcal serogroup B outbreaks (a total of 14 cases) caused by strains from two different clonal complexes. To control the outbreaks, students were immunized with a serogroup B meningococcal vaccine (Novartis) that was not yet licensed in the United States. The vaccine (referred to as MenB-4C) contains four components capable of eliciting bactericidal activity. Both outbreak strains had high expression levels of two of the vaccine antigens (subfamily B factor H binding protein [FHbp] and neisserial heparin binding antigen [NHba]); the university B outbreak strain also had moderate expression of a third antigen, NadA. We investigated the bactericidal activity of sera from mice immunized with FHbp, NHba, or NadA and sera from MenB-4C-immunized infant macaques and an adult human. The postimmunization bactericidal activity of the macaque or human serum against isolates from university B with FHbp identification (ID) 1 that exactly matched the vaccine FHbp sequence variant was 8- to 21-fold higher than that against isolates from university A with FHbp ID 276 (96% identity to the vaccine antigen). Based on the bactericidal activity of mouse antisera to FHbp, NadA, or NHba and macaque or human postimmunization serum that had been depleted of anti-FHbp antibody, the bactericidal activity against both outbreak strains largely or entirely resulted from antibodies to FHbp. Thus, despite the high level of strain expression of FHbp from a subfamily that matched the vaccine antigen, there can be large differences in anti-FHbp bactericidal activity induced by MenB-4C vaccination. Further, strains with moderate to high NadA and/or NHba expression can be resistant to anti-NadA or anti-NHba bactericidal activity elicited by MenB-4C vaccination.

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A Large Portion of Meningococcal Antigen Typing System-Negative Meningococcal Strains from Spain Is Killed by Sera from Adolescents and Infants Immunized with 4CMenB

Clinical and Vaccine Immunology ◽

10.1128/cvi.00669-14 ◽

2015 ◽

Vol 22 (4) ◽

pp. 357-360 ◽

Cited By ~ 13

Author(s):

R. Abad ◽

A. Biolchi ◽

M. Moschioni ◽

M. M. Giuliani ◽

M. Pizza ◽

...

Keyword(s):

Large Scale ◽

Vaccine Coverage ◽

Surrogate Marker ◽

Factor H ◽

Enzyme Linked Immunosorbent Assay ◽

Heparin Binding ◽

Protein Vaccine ◽

Typing System ◽

Meningococcal Group ◽

Group B

ABSTRACTA new vaccine (the 4CMenB 4-component protein vaccine [Bexsero], which includes PorA, factor H-binding protein [fHbp], neisserial heparin-binding antigen [NHBA], andNeisseriaadhesin A [NadA]) against serogroup B meningococci has recently been approved for use in people older than age 2 months in Europe, Australia, and Canada. Preapproval clinical efficacy studies are not feasible for invasive meningococcal disease because its incidence is low/very low, and the serum bactericidal antibody (SBA) titer (or the human SBA [hSBA] titer when human complement is used in the assay) has been used as a surrogate marker of protection. However, the hSBA assay cannot be used on a large scale, and therefore, a meningococcal antigen typing system (MATS) was developed. MATS combines conventional PorA genotyping with an enzyme-linked immunosorbent assay (ELISA) that quantifies both the expression and the cross-reactivity of antigenic variants. The assay has been used to evaluate the potential of the 4CMenB meningococcal group B vaccine to cover group B strains in several countries. Some recent data suggest that MATS is a conservative predictor of strain coverage. We used pooled sera from adolescents and infants to test by the hSBA assay 10 meningococcal group B strains isolated in Spain that were negative for the 3 antigens (n= 9) or that had very low levels of the 3 antigens (n= 1) by MATS. We found that all strains were killed by sera from adolescents and that 5 of the 10 strains were also killed, although at a low titer, by sera from infants. Our data confirm that MATS underestimates vaccine coverage.

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A Mutant Library Approach to Identify Improved Meningococcal Factor H Binding Protein Vaccine Antigens

PLoS ONE ◽

10.1371/journal.pone.0128185 ◽

2015 ◽

Vol 10 (6) ◽

pp. e0128185 ◽

Cited By ~ 10

Author(s):

Monica Konar ◽

Raffaella Rossi ◽

Helen Walter ◽

Rolando Pajon ◽

Peter T. Beernink

Keyword(s):

Binding Protein ◽

Factor H ◽

Mutant Library ◽

Protein Vaccine ◽

Vaccine Antigens

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Functional Mapping of YadA- and Ail-Mediated Binding of Human Factor H to Yersinia enterocolitica Serotype O:3

Infection and Immunity ◽

10.1128/iai.00314-08 ◽

2008 ◽

Vol 76 (11) ◽

pp. 5016-5027 ◽

Cited By ~ 45

Author(s):

Marta Biedzka-Sarek ◽

Saara Salmenlinna ◽

Markus Gruber ◽

Andrei N. Lupas ◽

Seppo Meri ◽

...

Keyword(s):

Yersinia Enterocolitica ◽

Alternative Pathway ◽

Outer Membrane Proteins ◽

Factor H ◽

Complement Alternative Pathway ◽

Human Host ◽

Serotype O ◽

Complement Resistance ◽

Sense And Respond ◽

Active Complement

ABSTRACT Yersinia enterocolitica is an enteric pathogen that exploits diverse means to survive in the human host. Upon Y. enterocolitica entry into the human host, bacteria sense and respond to variety of signals, one of which is the temperature. Temperature in particular has a profound impact on Y. enterocolitica gene expression, as most of its virulence factors are expressed exclusively at 37°C. These include two outer membrane proteins, YadA and Ail, that function as adhesins and complement resistance (CR) factors. Both YadA and Ail bind the functionally active complement alternative pathway regulator factor H (FH). In this study, we characterized regions on both proteins involved in CR and the interaction with FH. Twenty-eight mutants having short (7 to 41 amino acids) internal deletions within the neck and stalk of YadA and two complement-sensitive site-directed Ail mutants were constructed to map the CR and FH binding regions of YadA and Ail. Functional analysis of the YadA mutants revealed that the stalk of YadA is required for both CR and FH binding and that FH appears to target several conformational and discontinuous sites of the YadA stalk. On the other hand, the complement-sensitive Ail mutants were not affected in FH binding. Our results also suggested that Ail- and YadA-mediated CR does not depend solely on FH binding.

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Serum resistance ofAcinetobacter baumanniithrough the binding of factor H to outer membrane proteins

FEMS Microbiology Letters ◽

10.1111/j.1574-6968.2009.01820.x ◽

2009 ◽

Vol 301 (2) ◽

pp. 224-231 ◽

Cited By ~ 73

Author(s):

Sang Woo Kim ◽

Chul Hee Choi ◽

Dong Chan Moon ◽

Jong Sook Jin ◽

Jung Hwa Lee ◽

...

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Outer Membrane Proteins ◽

Factor H ◽

Serum Resistance

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STUDIES ON H. PERTUSSIS LIQUID CULTURES: III. LOCALIZATION OF SURFACE ANTIGENS BY MEANS OF FLUORESCENT ANTIBODY

Canadian Journal of Microbiology ◽

10.1139/m56-081 ◽

1956 ◽

Vol 2 (7) ◽

pp. 677-683 ◽

Cited By ~ 7

Author(s):

J. de Repentigny ◽

A. Frappier

Keyword(s):

Fluorescent Antibody ◽

Surface Antigens ◽

Fluorescent Antibody Technique ◽

Antibody Technique ◽

Solid Media ◽

Antigenic Properties ◽

Antigenic Material ◽

Capsular Antigens ◽

The Relationship

The fluorescent antibody technique was used in an attempt to clarify the relationship between the morphology of the surface of Haemophilus pertussis and the antigenic properties of its capsular antigens. First, specific antibodies were produced by injection into rabbits of agglutinogenic and protective surface washings of the bacilli. Then, these antibodies were made fluorescent and used to mark specifically and in situ the original capsular antigens at the surface of bacilli grown in liquid as well as on solid media. Thus was obtained morphological and specific evidence for the presence of a capsule containing antigenic material.

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In Silico Analysis of the Antigenic Properties of Iron-Regulated Proteins against Neisseria meningitidis

Applied Sciences ◽

10.3390/app10176113 ◽

2020 ◽

Vol 10 (17) ◽

pp. 6113

Author(s):

Md. Shahedur Rahman ◽

Chayon Biswas ◽

Polash Kumar Biswas ◽

Md. Ashraful Kader ◽

S. M. Nur Alam ◽

...

Keyword(s):

Neisseria Meningitidis ◽

Outer Membrane Proteins ◽

Treatment Strategies ◽

In Silico Analysis ◽

Analysis Data ◽

Bioinformatic Tools ◽

Antigenic Properties ◽

Potential Vaccine

Neisseria meningitidis is a commensal pathogen that causes infectious cerebrospinal disease in people of all ages. The multivariate role of six disease-causing polysaccharide serotypes is found to play a crucial role in developing vaccines (or general treatment strategies) to treat this emerging pathogen. Iron is a crucial transition metal for N. meningitidis. Proteomic analysis data could be valuable for vaccine design. Here, we conduct a comparative study using computational bioinformatic tools to identify the most effective iron-regulated outer membrane proteins (OMPs) as immunogenic targets for a potential vaccine against N. meningitidis. The basic properties of N. meningitidis OMPs are explored for flexibility, solubility, hydrophilicity, beta-turns, and overall antigenic probability. Results of our study suggest that iron-regulated OMPs are flexible and soluble in water with high densities of conformational B-cell epitopes. As such, they can be recommended as a novel candidate for a vaccine against N. meningitidis both in vitro and in vivo.

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Impaired Immunogenicity of a Meningococcal Factor H-Binding Protein Vaccine Engineered To Eliminate Factor H Binding

Clinical and Vaccine Immunology ◽

10.1128/cvi.00103-10 ◽

2010 ◽

Vol 17 (7) ◽

pp. 1074-1078 ◽

Cited By ~ 19

Author(s):

Peter T. Beernink ◽

Jutamas Shaughnessy ◽

Sanjay Ram ◽

Dan M. Granoff

Keyword(s):

Binding Protein ◽

Factor H ◽

Vaccine Antigen ◽

Mouse Strains ◽

Enzyme Linked Immunosorbent Assay ◽

Complement Factor ◽

Protein Vaccine ◽

Wild Type ◽

Bacterial Surface ◽

Cast Doubt

ABSTRACT Meningococcal factor H-binding protein (fHbp) is a promising antigen that is part of two vaccines in clinical development. The protein specifically binds human complement factor H (fH), which downregulates complement activation on the bacterial surface and enables the organism to evade host defenses. In humans, the vaccine antigen forms a complex with fH, which may affect anti-fHbp antibody repertoire and decrease serum bactericidal activity by covering important fHbp epitopes. In a recent study, fHbp residues in contact with fH were identified from a crystal structure. Two fHbp glutamate residues that mediated ion-pair interactions with fH were replaced with alanine, and the resulting E218A/E239A mutant no longer bound the fH fragment. In the present study, we generated the E218A/E239A mutant recombinant protein and confirmed the lack of fH binding. By enzyme-linked immunosorbent assay (ELISA), the mutant fHbp showed similar respective concentration-dependent inhibition of binding of four bactericidal anti-fHbp monoclonal antibodies (MAbs) to fHbp, compared with inhibition by the soluble wild-type protein. In two mouse strains, the mutant fHbp elicited up to 4-fold-lower IgG anti-fHbp antibody titers and up to 20-fold-lower serum bactericidal titers than those elicited by the wild-type fHbp vaccine. Thus, although introduction of the two alanine substitutions to eliminate fH binding did not appear to destabilize the molecule globally, the mutations resulted in decreased immunogenicity in mouse models in which neither the mutant nor the wild-type control vaccine bound fH. These results cast doubt on the vaccine potential in humans of this mutant fHbp.

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The stability of outer-membrane protein and antigen profiles of a strain of Bacteroides intermedius grown in continuous culture at different pH and growth rates

Canadian Journal of Microbiology ◽

10.1139/m91-060 ◽

1991 ◽

Vol 37 (5) ◽

pp. 368-376 ◽

Cited By ~ 3

Author(s):

G. H. Bowden ◽

N. Nolette ◽

A. S. McKee ◽

I. R. Hamilton

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Growth Rates ◽

Chemostat Culture ◽

Outer Membrane Proteins ◽

High Growth ◽

Novel Proteins ◽

Membrane Antigens ◽

The Stability ◽

Genotype Ii

The stability of the outer-membrane proteins and antigens of a strain of Bacteroides intermedius (VP1 8944 group genotype II) grown in contious culture at varying pH and growth rates (D = 0.025–0.2 h−1, pH 6.0–7.3) has been measured. The membranes showed nine major proteins (> 67–19.55 kilodaltons) and six major antigens (65–28 kilodaltons). Membrane proteins and antigens were stable under the conditions tested; the major proteins were detected in all membranes, and the antigen profiles tested with different antisera showed maximum similarities of 82–95%. Differences did occur in the amounts of membrane proteins synthesized; cells at high growth rates and those growing on the surfaces in the chemostat showed increased amounts of two proteins (40 and 32 kilodaltons) and possibly novel proteins of 24 and 25 kilodaltons. In addition, these membranes reflected increased synthesis or a change to increased reactivity of antigens between 20.5 and 24 kilodaltons. The results indicate stability of the expression of outer-membrane proteins and antigens in environments of differing pH and under different growth rates. However, the amount of these molecules synthesized can vary, and increases in certain proteins and antigens occur as the growth rate increases and the organisms grow on surfaces. Key words: Bacteroides intermedius, outer-membrane antigens, antigenic stability, chemostat culture, outer-membrane profiles.

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